I'd like to see something done about this.
I requested a very similar feature here:
Default Feed Rate and Maximum Feed Rate
I don't think my printer supports M203. For me, like in my post linked above, I need this done in software from within Simplify3D. Simplify3D internally calculates the extruder feed rate. It doesn't' show you this information, but it does keep track of it internally.
We need some way to control the extruder feed rate other than using
Default Printing Speed, which isn't really the correct way to control print speed. Print speed should be based on extruder feed rate. If we can set that, and have all the other settings based on that, then we can change layer height, extruder width, etc., and not worry about going faster than our printers can actually print a particular filament.
Nearly all slicers work backwards. Instead of print speed being controlled by the extruder feed rate, print speed is controlled by print head movement when extruding. This is absolutely the wrong way to operate a 3D printer. I don't know why this became the norm.
A printer cannot exceed a filament's maximum feed rate, no matter how slow or fast the print head is moving. The maximum feed rate doesn't depend on layer height, extrusion width, etc., it's a fixed value for a particular filament. But Simplify3D, and nearly all other slicers will change the feed rate if you change the layer height, or extrusion width, which should NOT happen. The feed rate should be constant. You can go under it a bit, but you can never go over it.
In Simplify3D, if you double the layer height, it will double the feed rate, and not tell you about it.
Likewise, if you double the extrusion width, it will double the feed rate.
Extruder feed rate shouldn't change when you change layer height or extrusion width. Instead, Simplify3D should change the
Default Printing Speed to keep it at or under the maximum extruder feed rate. It should let us set the
Default Feed Rate and
Maximum Feed Rate. No matter what other settings you change, no other setting should ever make the G-code go above a
Maximum Feed Rate setting. A
Default Feed Rate setting should control
Default Printing Speed, not the other way around.
A
Default Feed Rate and
Maximum Feed Rate setting should be stored as part of a filament's profile so that one set of these 2 settings is for PLA and another set is for ABS, etc.
If you don't change your printer's nozzle, or hot-end, then the maximum feed rate for a particular filament will never change. But currently most slicers don't take this into account. They calculate feed rate by multiplying
Extrusion Width by
Extrusion Multiplier by
Primary Layer Height by
Default Printing Speed. This is just not the right way to do it. Everything should stem from extruder feed rate, not the other way around.
